(Chirping sound.) That may not sound like much–but it’s the loudest animal in the world. For its size, that is. The insect called the water boatman is two millimeters long. And these peeps can be heard from a stream bottom by the human ear.

Animals are generally constrained by the mechanics of size. But small creatures need to be heard as well. Researchers thought some freshwater species might rely on sound because of poor visibility. So they collected water boatmen from a stream and pond in France. They recorded 13 males doing their thing. They measured the sound level and the insects’ bodies. And they compared those figures with 227 other loud species, like elephants. And relative to its body, the little water boatman made the biggest racket, maxing out at 99 decibels. The research was published in the journal Public Library of Science One. [Jérôme Sueur, David Mackie, James Windmill, "So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae)"]

The scientists say they haven’t figured out exactly how the tiny creature produces such volume–in part it comes from rubbing part of its genitalia against its abdomen. But understanding the amplification could help us improve our own acoustic technology. Using different techniques, of course.